Description of the Related Art
Where spinning machines such as roving frames and ring spinning frames are installed in a factory-building having a single floor or several floors, when full packaged roving bobbins are to be transported to positions adjacent to the ring spinning frames, usually a transporting system is used whereby full packaged roving bobbins doffed from respective roving frames are placed in transporting carriers which are moved along the floor and delivered to a position allocated for receiving them. If the roving frames and the ring spinning frames are installed on different floors, the transporting carriers are moved from one floor to the other by an elevator, and the full packaged roving bobbins are then taken out of the transporting carriers and mounted on the creel of the ring spinning frame concerned, by utilizing bobbin hangers from which the full packaged roving bobbins are suspended.
As is well known in this field, when such a transporting system is used, there is a considerable possibility of damage occurring to the outside layers of the full packaged roving bobbins, due to frictional contact of the full packaged rovings bobbins with other full packaged roving bobbins or with the inside wall of the carrier, and further, this transporting system incurs manual operating costs. To alleviate the disadvantages of the above-mentioned transporting system, an improved transporting carrier was disclosed in Japanese Examined Patent Publication Showa No. 54 (1979)-44786. Nevertheless, this transporting carrier has a complicated construction, and thus is more expensive to manufacture, and still requires manual operation. Therefore the above-mentioned problems cannot be solved by adopting this type of transporting carrier.
To fundamentally solve the above-mentioned problems, a unique apparatus for doffing full packaged roving bobbins from a roving frame and transporting doffed full packaged roving bobbins to positions for carrying out the roving bobbin changing operation for a ring spinning frame was proposed in Japanese Unexamined Patent Publication Showa No. 61 (1986)-201029, which corresponds to U.S. Pat. No. 4,369,621, by the applicant of the present application. In the apparatus of this invention, each roving frame is provided with an automatic doffing apparatus by which all full packaged roving bobbins are simultaneously doffed from the roving frame and received by respective pegs on a conveyor belt arranged at an adjacent position in front of the alignment of the flyers, and a holding plate provided with a pair of pegs for temporarily holding the full packaged roving bobbins is displaced upwards from the discharging end portion of a conveyor belt of the doffing apparatus to the above-mentioned bobbin hangers of the bobbin carriage, which can be displaced along a guide rail system suspended from the ceiling of the floor on which the ring spinning frames are installed. After the full packaged roving bobbins are transferred from the pegs of the holding plate to the corresponding bobbin hangers of the bobbin carriage, the holding plate is displaced downwards to be returned to the lowermost position thereof at which the above-mentioned transfer of the full packaged roving bobbins from the conveyor belt of the automatic doffing apparatus to the holding plate is carried out. Accordingly, it takes a long time to complete the transfer of all of the full packaged roving bobbins doffed from a roving frame to the respective bobbin hangers of the bobbin carriage, and since this type of roving frame starts a normal spinning operation as soon as the automatic doffing operation is completed, the following problems arise. Namely, since it is impossible to eliminate the roving piecing operation for a certain spinning unit of the flyers, if the full packaged roving bobbins are still on the conveyor belt at the time when the above-mentioned piecing operation must be carried out before starting the normal spinning operation of the roving frame, these full packaged roving bobbins hinder the smooth start to the operation of the roving frame, particularly, since a quick start of the spinning operation is usually required. Accordingly, the speed of the operation of transferring all of the full packaged roving bobbins from the conveyor belt of the automatic doffing apparatus to the bobbin hangers of the bobbin carriage by the above-mentioned proposed system must be increased, particularly when several floors, i.e., more than three floors, are utilized in such a factory.